Make Columns in Contact Form 7

.one-half,

.one-third {
position: relative;
margin-right: 4%;
float: left;
margin-bottom: 20px;

}

.one-half { width: 48%; }
.one-third { width: 30.66%; }

.last {
margin-right: 0 !important;
clear: right;
}

@media only screen and (max-width: 767px) {
.one-half, .one-third {
width: 100%;
margin-right: 0;
}
}